With the promulgation of connected devices, text-based communication has increased in importance over the last several decades. Examples of text-based chat used on devices that are sometimes or always online include mobile phone Short Messaging Services (SMS) and Multimedia Messaging Services (MMS), Online Chat, the Internet Relay Chat network, e-mail and avatar-based chat applications like IMVU.com, and text broadcasting/status updating services like Twitter and Facebook.
Text-based chat can be based on a synchronous, interactive dialog, or can be based on an asynchronous dialog, such as through mobile phone SMS messages, Twitter, online forums, or e-mail. The difference between synchronous and asynchronous communications is that, in synchronous communications, both sender and receiver of a message must be connected to the messaging exchange at the same time, whereas with asynchronous messaging, a sender leaves a message in storage, which is later retrieved and interpreted by the recipient. The best asynchronous messaging systems, such as SMS and Twitter, may appear close to synchronous in nature, because they support, communication latencies of as low as a few seconds, but the technology is still asynchronous and there are limitations to the interactivity afforded by asynchronous communication implementations.
Because of limitations inherent in text transmission, conventions have evolved to express states of mind, the difference between joking and seriousness, and short-hand for various kinds of common expressions. However, these conventions have not sufficiently improved the limitations inherent in conventional text transmission.